Publication 15-T (2026), Federal Income Tax Withholding Methods
Worksheet 1A, pay periods, W-4 Steps 2–4, annual percentage-method tables, standard annual adjustment, rounding boundary.
Open Internal Revenue Service source ↗Two sides of the same pay period
Employee withholding is not the employer’s full cost
Social Security and Medicare normally have employee and employer shares. Additional Medicare has an employee withholding rule and no employer match.
| 2026 line | Employee | Employer | Annual boundary |
|---|---|---|---|
| Social Security | 6.2% | 6.2% | $184,500 wage base |
| Medicare | 1.45% | 1.45% | No wage base |
| Additional Medicare withholding | 0.9% | No match | Employer begins above $200,000 paid |
Employer cost remains incomplete here.
FUTA, state unemployment, workers’ compensation, benefits, paid leave and other costs are not included, so this page does not claim to calculate total employer payroll cost.
Publication 15 (2026), Employer's Tax Guide
Social Security employee and employer rates, Medicare rates, Social Security wage base, Additional Medicare withholding threshold.
Open Internal Revenue Service source ↗Contribution and Benefit Base
$184,500 Social Security wage base, 6.2% employee and employer rates.
Open Social Security Administration source ↗Form W-4 (2026), Employee's Withholding Certificate
field labels and employee-election boundaries.
Open Internal Revenue Service source ↗